Apparatus for bridging and cementing well casing



B. L. AUSTIN July 29, 1958 APPARATUS FOR BRIDGING AND CEMENTING WELL CASING Filed Aug. 19, 1952 2 Sheets-Sheet 1 Inl 1N V EN TOR.

BEM/AMW ZEW/s Ausf/N,

rroeA/E V5 July 29 1958 B. L. AUSTIN 2,845,130

APPARATUS FOR BRIDGING AND CEMENTING WELL CASING Filed Aug. 19. 1952 2 Sheets-Sheet 2 INVENTOR.

r TOQA/Eys ICC Patented July 29, `195s APPARATUSV FOR BRIDGING AND CEMENTING WELL CASING Benjamin Lewis Austin, Long Beach, Calif., assigner to Baker Oil Tools, llnc., Los Angeles, Calif., a corporation of California Application August 19, 1952, Serial No. 305,137

16 Claims. (Cl. 166-187) The present invention relates to subsurface well apparatus, and more particularly to apparatus adaptedto form part of a well casing, or similar conduit string,

through which cementitious materials are displaceable for deposition behind the conduit string. y

In certain well bores, it is desirable to run casing therein and be capable of conditioning the hole by pumping circulating fluid out through the lower end or shoe of the casing. Following the hold conditioning operation, the casing is cemented, but no cementitious material Vis to be deposited below the lower endy of the casing, or below some other predetermined location along its length.

An object of the present invention is to provide improved apparatus for accomplishing the above mentioned desirable results.

Another object of the invention isto provide improved well casing cementing apparatus that enables tluid circulation to be obtained through the lower end of the casing, and which can be operated to provide an annular bridge between the casing and wall of the surrounding well bore, to preclude cementitious material ejected from the casing above the bridge from descending therebelow,y n

A further object of thel invention is to provide well casing cementing and bridging apparatus inwhich an annular bridge of pliant, elastic material can be provided between the apparatus and wall ofV the well bore, the pliant, elastic material being expandible to a relatively great extent outwardly from the casing. y

Yet another object of the invention is to provide well casing cementingv and bridging apparatus, in which normally closed side ports are provided above an inflatable packing type of annular bridge device surrounding the casing.

Still another object of the invention is to provide well casing cementing andbridging apparatus, in which normally closed side ports are provided above an inatable type of annular bridge device surrounding the casing, and in which the inflation of the bridge device is controlled to a predetermined degree. More specifically, the extent of inflation of the bridge device is held to a predetermined maximum unit pressure, or to a predetermined maximum value.

This invention possesses many other` advantages, and has other objects which may be made more clearly ap.- parent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is yto be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims. v l

Y Referring to the drawings:

Figure 1 is a longitudinal section throughone, form of apparatus embodying the invention, with thefparts dis-V posed in their initial position which 'th'eywocc'upy during lowering of the apparatus in the well bore;

Fig. 2 is a cross-section taken along` the line 2-2 on v the parts in still another relative position.

The apparatus is illustrated in the'drawings as constituting a casing shoe A adapted to form the lower terminal portion of a casing string B extending to the top of the well bore. It is to be understood, however, that the apparatus could also be designed for incorporation at an intermediate point in the casing string, under which conditions, it would be called a casing collar. l

The casing shoe includes an outer tubular member 10 having an upper threaded box portion 11 for attachment to `the lower pin end of an adjacent ,casing sectionV B. This tubular member has a lower abutment ring 12 threaded on its lower end, which contains a lower retaining ring 13, the latter part being suitably attached to an inflatable rubber packingy sleeve 14 surrounding the tubular member, as by use of the interlocked flanges 15, I6 orr the ring and packing sleeve. The upper end of the packing sleeve is similarly attached to an upper retaining ring 17 confined within an upper abutment 18 attached to the tubular member 10 in any suitable manner, as through use of welded material 19. The' retainer rings 13, 17 may be secured to their respective abutments 12, 18v against movement by means of the setscrews 20.

The packing sleeve 14 normally assumes a retracted position disposed within the peripheral contines ofl the retainer rings 13, 17, but is adapted to be inflated by tluid pumped outwardly through the side ports 21 in the tubular member 10 and into the interiorof the rubber packing sleeve. Such fluid is incapable of owing back through lthe ports 21 because of the presence of av back pressure valve, in the form of a rubber band or sleeve 22 encompassingl the tubular member 10v within a peripheral groove 23'therein and disposedA over the ports. The fluidi entering the rubber packing sleeve 14 is prevented from leaking out between the retainer rings' 13, 1'7 and tlie tubular member 1f)Y by suitable seal rings 24 inthe retainer rings bearing against theperiphery Vof the tubular member. Y

Inflation of the rubber packing sleeve 14 occurs as a result of forcing a suitable entrapped liquid 25, such as light oil or water, in the tubular member 10 through the ports 21. This liquidy is contained Vwithin an annular chamber 26 formed between alcentral` upper valve body 27 rand the inner wall 28 of the outer tubularmember. The upper valve body is provided with a flange 29restin`g upon a shoulder 30 in the outer tubular member 10, the valve body being prevented from moving upwardly with respect to the outer tubular member by a plug of cement 3'1 resting upon the ilanrg'e 29'and received withininternal grooves 32 formedV circumferentially around the interior of the tubular member 10. The upper valve body 27 extends upwardly from its flange 2,9 andl terminates in a'n upper outwardly flaring upper portion 33 which'V extends outwardly into'the cementitious material o'f the plug 31, the upper' end34 of theplug preferably tapering' in 'an upward and outward direction `from the upper end of the valve` body, to provide a guide for a valve element described hereinbelow. l

The'Z lower portion of the generally tubular valvebody f 27 is piloted withina lower valve' body 35, a1 shoulder 36j on the'upper valve 4body resting upon an int'urned lower ange 37l onthe lower valve b'odyl35'. This'v latter valve body has "an .upper ange or head .osfextendinfg` out; wardly tothe wal1-28 of theouter, tubular member-I0', to fornrrthei lowerpo'rtionof tlie annular chamber 26 that contains the entrapped liquid 25. The lower valve body 35 is anchored to a cementitious plug 39 by means of the longitudinally spaced ribs 40, the plug itself being cast into internal circumferential grooves 41 lformed in the lower portion of the tubular member 10. The lower end of the lower plug 39 preferably has a rounded nose 42, to constitute a guide for facilitating passage of the casing string past obstructions that might be encountered in the well bore. f

Leakage between the lower portion of the upper valve body 27 and lower valve body 35 is prevented by a suitable seal ring 43 carried in the lower body and sealingly engaging the periphery of the upper valve body. Similarly, leakage between the lower valve body head 38 and the inner wall 28 of the outer tubular member 10 is prevented by a suitable side seal 44 in the head engaging the wall ofthe tubular member.

It is to be noted that there is an annular space 45 between the upper and lower valve body members 27, 35 above their point of contact with each other, and this space communicates with the annular chamber 26, and also with a ller port 47 extending through the wall of the lower valve body 35. A back pressure valve ball housing member 48 is disclosed as being threaded on the lower body 35, having a closure portion 49 adapted to extend over the ller port 47, in order to close the same. Leakage of fluid from the chamber 26 and out through the ller port 47 is prevented by providing suitable side seals 50 in the ball housing on opposite sides of the filler port.

When the chamber 26 is to be lled with the liquid 25, the ball housing 48 is not threaded onto the lower valve body 35. Accordingly, iluid can be deposited through the filler port 47, and through the annular ller passage 45 into the annular chamber 26, after which the ball housing 48 can be threaded in place into the position disclosed in the drawings, to prevent loss of the liquid rfrom the annular chamber 26 outwardly through the iiller passage 45 and liller port 47.

The ball housing 48 contains a back pressure ball valve member 51 which preferably has a specific gravity so as to make it buoyant in cement slurry, this valve member moving upwardly into engagement with a valve seat 52 on the lower end of the upper valve body 27, to enable the entire casing string to be iloated downwardly through the fluid in the well bore. Leakage between the ball element 51 and the seat 52 is prevented by a suitable seal ring 53 in the seat engageable with the ball valve member. 'Ihe ball valve member, however, does not preclude downward pumping of tluids through the shoe. When such pumping occurs, the ball valve 51 moves downwardly from its seat and comes to rest upon a suitable stop 54 in the form of a pin secured to and extending transversely across the lower portion of the ball housing 48.

In eiect, the upper valve body 27 and tubular member provide an annular cylinder 26. An annular piston 55 is slidable in this cylinder, initially occupying a position at the upper portion of the entrapped liquid ,25 in the annular chamber. The piston is normally held in this upper position by one or more frangible elements 56, in the form of shear screws, securing it to the upper valve body 27. Access for a tool to assemble these screws in place may be had through suitable outer holes 57 in the piston member. Leakage of iluid between the piston and the valve body 27 and outer tubular member 10 is prevented by suitable side seals 58 in the piston engaging these latter parts. t

When' the piston 55 is moved downwardly, theentrapped liquid 25 is forced out through the ports 21 and past the check valve 22, out into the interior of the rubber packing sleeve 14, inflating the latter and causing it to expand outwardly against the wall of the well bore C. The piston is movable downwardly to the maximum extent in which it engages the Vhea d`38 of the lower'valve Y 4 body 35. As a result, only a predetermined maximum volume of liquid can he pumped into the inilatable packing sleeve 14, insuring against its wall being thinned down to too great an extent.

Pressure applied to the Huid in the well casing B is availed of to force the piston 55 downwardly in the annular chamber 26. This uid will pass from the interior of the apparatus through one or more side ports 59 in the upper valve body 27 above the piston 55. The ability of the pressure to be built up in the tluid in the casing string depends upon the closing of the central passage through the apparatus below the ports 59. Such closing occurs as a result of the seating of a valve element 60, such as a trip ball, which is dropped or pumped down the casing string B and into engagement with a seat 61 provided in a sleeve valve 62 slidable in the upper housing or valve body 27. This sleeve valve 62 initially occupies an upper position, in which it is disposed over side ports 63 formed through the upper valve body 27 above its ange 29, these ports being aligned with passages or ports 64 extending through the cement plug 31 and the outer tubular member 10. Leakage of fluid between the sleeve valve 62 and the housing 27 is initially prevented by side seals 65 in the upper portion of the sleeve valve on opposite sides of the body ports 63.

The sleeve valve 62 is held in an upward position by one or more shear screws 66 attaching it to the upper valve body 27. When the shear screws 66 are intact, the upper portion 62a not only closes the ports 63, but intermediate ports 67 in the sleeve valve are arranged in alignment with the housing ports 59, providing a passage to the annular chamber 26 above the piston 55.

The upper valve body 27 is also provided with a relief port 68 at the lower portion of the annular chamber 26, which is closed initially by the lower portion 62b of the sleeve valve 62, there being seal rings 69 carried by the sleeve valve and disposed on opposite sides of this port when the shear screws 66 attaching the sleeve 62 to the upper valve body 27 are intact. Disposed in the sleeve valve body 27 above the upper seal ring 69 are one or more relief ports 70, there being another seal ring 71 carried by the sleeve valve and slidably engaging the wall of the upper valve body 27 below the upper sleeve valve ports 67.

The parts of the apparatus occupy the positions illustrated in Fig. 1 when the shoe A is secured to the lower portion of the casing string B. The apparatus is lowered through the fluid in the well bore C, with the casing sections B thereabove, until the location is reached at which the casing shoe is to be disposed. During this time, the packing sleeve 14 occupies its retracted position. Circulating fluid may now be pumped down the casing string B, and will pass outwardly through its lower end, continuing up around the exterior of the casing string without interference by the packing sleeve 14, for the purpose of conditioning the well bore C preparatory to cementing. All of the tluid must pass down through the central passage through the shoe, since the side cementing ports 63, 64 are closed by the sleeve valve 62.

After the well bore has been properly conditioned, the trip ball 60 may be allowed to gravitate, or is pumped, down the casing string B, until it engages its companion seat 61 in the sleeve valve 62 below the ports 67. Such engagement precludes further downward passage of lluid through the shoe. Accordingly, pressure can be built up inthe casing string above the ball 60, this iluid under pressure passing outwardly through the ports 67, 59 and acting uponY the upper portion of the annular piston 55. Thescrews 56 securing this piston to the upper valve body 27 have a combined shear strength that is substantially less than the s hear strength of the screws 66 securing the sleeve valve 62 to the upper body 27. As a result, when suicient pressureris built up in the casing string, Ythe upper shear'screws 56 will be disrupted, the lpiston its inflation.

55 moving downwardly and forcingthe liquid Y25 inthe chamber 26 out through the ports 21 and past the check valv e 22 to inilate` the sleeve ,14 outwardly and into snug sealing4 engagement with the wall of the confining well bore C. Y

The piston 55 can move downwardly to the extent limited by its engagement with theV head 38 of the lower valve body 35. However, if the pressure imposed on the entrapped liquid 25 and within the inated packing sleeve 14 exceeds a predetermined value, which corresponds to the shear strength of the screws 66 attaching the sleeve valve member 62 to the upper-valve body 27, then such shear screws 66 will be disrupted before the piston 55 reaches the lower limit of its travel, and the sleeve valve 62 will be shifted downwardly until rit engages a stop shoulder 75 at the lower portion of the upper body, as disclosed in Fig. 4. Such downward shifting of the sleeve valve 62 opens the cementing ports 63, 64 in the apparatus, and also disposes the relief port 70 of the sleeve valve in communication with the release port 68 in the housing 27, all as disclosed in Fig. 4. At the same time, the uppermost seal ring 65 ofthe sleeve valve 62 is located at least slightly below the port 59 leading into the annular chamber 26 above the piston 55. Accordingly, the liquid 25 in the chamber-26 below this piston that may now remain can pass outwardly through the release and relief ports 68, 70, and flow down through the shoe passage and outwardly therefrom, the fluid pressure present in the casing string above the ball 60 passing through the ports 59 land into the chamber 26 to force the piston 55 downwardly to its full extent, as disclosed in Fig. 4.

The packing sleeve 14 has, therefore, been inflated outwardly into iirm leakproof engagement with the wall of the confining well bore C, andthe bleeding oit of the pressure in `the annular chamber 26 below the piston 55 allows the back pressure valvef22 to close across the ports 21 andentrap the liquid 25 in the inflated sleeve. Inasmuch as the cementing ports 63, 64 are now open, cement slurry, or other cementitious material, may be pumped down the casing string B, and Yall such cement slurry must pass outwardly through the open ports, since the trip ball 60 is completely closing the central passage through the shoe. This cement slurry will pass outwardly through the ports 63, 64 and will flow upwardly along the casing string B. The expanded packing sleeve 14 prevents any of the cement slurry from dropping downwardly below the sleeve 14, insuring that the well bore below the packing sleeve will be completely freefrom the cement. y

After the required volume of cement has been deposited through therports 63, 64 and behind the casing B, the casing head at the top of the hole may be closed in to prevent the cement from flowing back into the casing string. When the cement has hardened, a suitable tool can be run in the casing string to drill out all of the mechanism within the outer tubular member 10. Such mechanism is all preferably made of readily drillable materials, so as to disintegrate under the action of a drill bit without diculty.

From the foregoing description, it is apparent that an apparatus has been provided in which the fluid can be circulated down through the casing string, all of it passing out through the lower end thereof, in order to properly condition lche hole and to wash laway any bridges that might be encountered during lowering of the casing string in the well bore. The side cementing ports 63, 64 are initially closed and the packing sleeve 14 may be expanded outwardly to a considerable extent, in view of However, the extent of expansion is still limited by the volume of entrapped liquid 25 in the annular chamber 26, to guard against inadvertent bursting of the packing sleeve. In addition, the retention of the packing sleeve in' packed-off condition is assured, since it cannot be subjected to any excessiveV pressure. If the pressure exceeds a predetermined amount, then the shear screws 66 attaching the sleeve valve 62 to lthe upper valve body 27 will be disrupted, placing the relief port 70 in communication with the release port 68 in the,` housing, and enabling the excess liquid 25 in the chamberto ow outwardly thereof. Following the full expansion of the packing sleeve 14 against the forrnationwall, in order to bridge the annular space between the casing string B and such formation wall, the requisite Yquantity of cement slurry can be pumped out through the, cementing ports 63, 64' with assurance that noneof the cement slurry will drop down below the packing sleeve 174.

The inventor claims:` i

1. In apparatus of the character described? tubular meansadapted to form part ofa conduit string positionable in a well bore; an inflatable packing 4structure on said tubular means; said tubular means having an annular chamber therein communicable with the interior of said packing structure; means in said chamber responsive to uid under press-ure in said tubularl means for forcing an inflating fluid in said chamber into said structure to iniiate the same; means providing fluid communication between the interior of -said tubular means and said means in said chamber; said tubular means having a port to one side of said structure through which fluid can pass between the interior and exterior of said tubular means; and valve means movable along said tubular means to control passage of uid through said port. 2. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore; an inflatablepacking structure on said tubular means; said tubular means having an annular chamber therein communicable with the interior of said packing structure; a piston slidable in said chamber and responsive to iluid under4 pressure in said tubular means to force an inflating fluid in said chamber into said strucl ture to, inate the same; means providing fluid communication between the interior of said tubular means and `said piston; said tubular means having ia port to one side of saidstructure through which fluid can pass between the interior and exterior of said tubular means; and valve means movable along said tubular means to control passage of Huid through said port.

3. In apparatus of the character described: vtubular means adapted to form part of a conduit string positionable in a well bore; an inflatable packing Vstructure on said tubular means; said tubular means having an annular chamber therein communicable with the interior of said packing structure; means in said chamber responsive to uid under pressure in said tubular means for forcing an inating fluid in said chamber into said structure to inflate the same; means providing fluid communication between the interior of said tubular means and said means in said chamber; said tubular means having a port to one side of said Structure through which fluid can pass between the interior and exterior of said tubular means; valve means movable along said tubular means to control, passage ofA fluid through said port; and means for bleeding inating uid from said chamber when the pressure of such inflating fluid reaches a predetermined value.`

4. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore and having a passage therein; an inflatable packing structure on said tubular means; said tubular means having an annular chamber therein com'- municable with the interior of said packing structure;

rmeans in said chamber responsive to fluid under pressure in said tubular means for forcing an inating fluid in said chamber into said structure to inflate the same; means providing fluid communication between the interior of said tubular means and said means in said chamber; said tubular means having a port to one side of said structure through which fluidrcan pass between the interior and exterior of said tubular means; and a sleeve valve insaid passage initially closing said port and shiftable longitud-finally of said tubular means to a position opening said 5. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore and having a passage therein; an inflatable packing structure on said tubular means; said tubular means having an annular chamber therein communicable with the interior of said packing structure; a piston slidable in said chamber and responsive to fluid under pressure in said tubular means to force an inffatng fluid in said chamber into said structure to inflate the same; said tubular means having a side port to one side of said structure through which fluid can pass between the interior and exterior of said tubular means; a sleeve valve in said passage initially closing said port and shiftable longitudinally of said tubular means to a position opening said port; means including a port in said sleeve valve and communicable with said chamber for directing fluid in said tubular means and sleeve valve into said chamber to move said piston in said chamber.

6. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore and having a passage therein; an intlatable packing structure on said tubular means; said tubular means having an annular chamber therein communicable with the interior of said packing structure; means in said chamber responsive to fluid under pressure in said tubular means for forcing an inflating fluid in said chamber into said structure to inflate the same; said tubular means having a port to one side of said structure through which fluid can pass between the interior and exterior of said tubular means; a sleeve valve in said passage initially closing said port and shiftable longitudinally of said tubular means to a position opening said port; a bleeder port communicating with said chamber and which is closed initially by said sleeve valve; said sleeve valve being shiftable to a position opening said bleeder port.

7. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore and having a passage therein; an inflatable packing structure on said tubular means; said tubular means having an annular `chamber therein cornmunicable with the interior of said packing structure; a piston slidable downwardly in said chamber and responsive to fluid under pressure in said tubular means to force an intlating fluid in said chamber into said structure to inflate the same; said tubular means having a side portabove said structure through which fluid can pass between the interior and exterior of said tubular means; said tubular means having a relief port at the lower portion of said chamber for bleeding inflating fluid from said chamber; and a sleeve valve in said passage initially closing said side'port and relief port and shiftable downwardly in said tubular means to a position opening said side port and relief port.

8. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore and having a passage therein; an inflatable packing structure on said tubular means; said tubular means having an annular chamber therein communicable with the interior of said packing structure; a piston slidable downwardly in said chamber and responsive to fluid under pressure in said tubular means to force an inflating fluid in said chamber into said structure to inflate the same; said tubular means having a side port above said structure through which fluid can pass between the interior and exterior of said tubular means; said tubular means having a relief port at the lower portion of said chamber for bleeding inflating fluid from said cham-ber; a sleeve valve in said passage initially closing said side port and relief port and shiftable downwardly in said tubular means to a position opening said side port and relief port; Vfirst frangible means initially securing said piston to said tubular means in an elevated position;

and second frangible means initially securing said sleeve valve to said tubular means in a position closing said side port and relief port.

9. Apparatus as defined in claim 8, wherein said first frangible means has a lesser strength than said second frangible means.

l0. In apparatus of the character described: an outer tubular member having a side port and adapted to form part of a conduit string positionable in a well bore; an inner tubular member in said outer member and forming an annular chamber therewith; an inflatable packing structure on said outer member below said side port, said structure communicating with said chamber; an annular piston in said chamber slidable downwardly along said members to force an inating fluid in said chamber into said structure to inflate the same; said inner member having a relief port at the lower portion of said chamber for bleeding infiating fluid from said chamber; a tubular sleeve valve slidably mounted in said inner member and initially closing said side port and relief port, said sleeve valve having a port for the passage of fluid in said sleeve valve into said chamber above said piston; first frangible means initially securing said piston to one of said members in an elevated position; and second frangible means initially securing said sleeve valve to said inner member in a position closing said side port and relief port.

ll. In apparatus as defined in claim 10, means adapted to be sent down the conduit string into engagement with the sleeve valve below the sleeve valve port to close the central passage through the sleeve valve and enable the piston and sleeve valve to be subjected to the pressure of fluid in the conduit string.

l2. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore; an Iinflatable packing structure on said tubular means; said tubular means having a passage communicating with the interior of the conduit string, said passage being initially open to permit fluid to flow downwardly through the conduit string and passage and discharge from said passage into the well bore below said packing structure; means for feeding fluid into said structure to inflate the same including instrumentalities in fluid communication with said passage; said tubular means having a port above said structure through which fluid can pass between said passage and the exterior of said tubular means; valve means movable along said tubular means to control passage of fluid through said port; and means adapted to be disposed below said fluid feeding means for closing said passage against downward flow of fluid therethrough after the conduit string has been positioned in the well bore, whereby pressure can be built up in said passage to be transmitted through said fluid feeding means to inflate said packing structure.

13. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore; an inflatable packing structure on said tubular means; said tubular means having a passage communicating with the interior of the conduit string, said passage being initially open to permit fluid to flow downwardly through the conduit string and passage and discharge from said passage into the well bore below said packing structure; means for feeding fluid into said structure to inflate the same including instrumentalities in fluid communication with said passage; said tubular means having back pressure valve means or preventing inflating fluid from bleeding from said structure; said tubular means having a port above said structure through which fluid can pass between said passage and the exterior of said tubular means; valve means movable along said tubular means to control passage of fluid through said port; and means adapted to be disposed belowsaid fluid feeding means for closing said passage against downward flow of fluid therethrough after the conduit string .has been positioned in the well bore,V whereby pressure assenso can be built up in said passage to be transmitted through said fluid feeding means to inate said packing structure.

14. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore; an inflatable packing structure on said tubular means; said tubular means having a passage communicating with the interior of the conduit string, said passage being initially open to permit fluid to ow downwardly through the conduit string and passage and discharge from said passage into the well bore below said packing structure; means for feeding fluid into said structure to inflate the same including instrumentalities in fluid communication with said passage; said tubular means having a port disposed to one side of said structure through which fluid can pass between said passage and the exterior of said tubular means; valve means movable along said tubular means to control passage of uid through said port; and means adapted to be disposed below said iluid feeding means for closing said passage against downward ilow of fluid therethrough after the conduit string has been positioned in the well bore, whereby pressure can be built up in said passage to be trans'- rnitted through said fluid feeding means to inate said packing structure.

15. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in a well bore; an inatable packing structure onV said tubular means; said tubular means having a passage communicating with the interior of the conduit string, said passage being initially open to permit uid to ow downwardly through the conduit string and passage and discharge from said passage into the well bore below said packing structure; means for feeding uid into said structure to inflate the same including instrumentalities in fluid communication with said passage; said tubular means having a port above said structure through which fluid can pass between said passage and the exterior of said tubular means; a shiftable sleeve valve in said passage disposable over said port to close said port; and means adapted to be disposed below said uid feeding means for closing said passage against downward flow of fluid therethrough after the conduit string has been positioned in the well bore, whereby pressure can be built up in said passage to be transmitted through said fluid feeding means to inate said packing structure.

16. In apparatus of the character described: tubular means adapted to form part of a conduit string positionable in -a well bore and having a passage therein communicating with the interior of the conduit string; an inilatable packing structure on said tubular means; means for feeding fluid into said structure to inflate the same including instrumentalities in fluid communication with said passage; said tubular means having a port above said structure through which fluid can pass between said passage and the exterior -of saidtubular means; a shiftable tubular sleeve valve in said passage disposed initially over said port to close said port; and means adapted to engage said sleeve valve below said fluid feeding means to close a passage through said valve and said tubular means passage against downward ow of ulid therethrough after the conduit string has been positioned in the well bore, whereby pressure can be built up in said tubular means passage to be transmitted through said uid feeding means to inflate said packing structure and to shift said valve downwardly to port opening position.

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